Abstract

The dependence of the Hall carrier density on bismuth concentration, n, p = f(N-Bi), in PbSe:Bi:Se/BaF2 films has been studied. The films were grown by vacuum condensation from two independent molecular beams (PbSe:Bi and Se-2) mixed directly at the surface of a (111)BaF2 substrate heated to 350 degreesC. The bismuth concentration in the stock was 0-0.3 at. %. Two specific portions can be distinguished in the experimental n, p = f(N-Bi) dependence. At N-Bi > 0.0375 at. %, the electron density is close to N-Bi; at low bismuth concentrations, N-Bi < 0.0375 at. %, the linear run of the n = f(N-Bi) dependence is violated, and the conduction changes to p-type. All the doped films under study are saturated with selenium. This is a necessary condition for obtaining the highest electron densities in the films at N-Bi corresponding to the linear portion of the n = f(N-Bi) dependence. The resultsare discussed in terms of a thermodynamic model of the impurity interaction with intrinsic defects in PbSe, taking into account the amphoteric behavior of bismuth atoms in lead selenide. (C) 2001 MAIK "Nauka/Interperiodica".
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodiciDocumento generato il 07/06/20 alle ore 08:35:47